Automatic player.



.PATENTED AUG. 4, 1908.

G. W. PAULSGN. AUTOMATIC PLAYER. APPLIGATION FILED NOV. 2, 1909.

4 SHEETS-SHEET 2.

PATENTED AUG. 4, 1908. G. W. PAULSON.

AUTOMATIQ PLAYER.

' D 2 1906. APPLlOATION FILE NOV 4 SHEETS SHEET 3.

mmmmm v l. 150 152 g UNITED s'rarrns rats GUSTAF WM. PAULSON, OF BOSTON, MASSACHUSETTS, ASSIGNOROF ONE-HALF 'IO RUDOLF PAULSON, OF CAMBRIDGE, MASSACHUSETTS.

euros term 'PLAYEn.

To all whom. it moi concern:

Be it known that 1, GUSTAF WM. PAULSON,

of Boston, in the county of Suffolk and State This invention relates to automatic players.

More particularly, it relates to improvements in apparatus for playing automatically instruments having a key-board like a )iano, especially those operated pneumatically.

it comprises features of novelty in a num oer of details and in the arrangement and cim'ibination of the various details and parts as hereinafter set forth.

The objects of the invention are to provide apparatus of the class described which can be 11. is an enlarged view of the music rolls, and

installed in an upright piano casing of the sort ,now commonly furnished with non-automatic playing pianos, thus enabling owners as well as makers of such pianosto apply the apparatus as an attachment to ianos already made in a simple and relatively inexpensive manner, the parts being inclosed within the casing.

The details of the invention will appear from the following description and from the accompanying drawings, which represent an embodiment of the invention.

In the drawings higure 1 represents a ver tical cross-section of an ordinary pianoforte embodying the invention. Fig. 2 is a front view of the same partly broken away. Fig. 3 is a sectional plan view eorrespomling to line 33 of Fig. l, in. which the ordinary pedal mechanism is omitted. Fig. l is a front elevation of the valve chambers, being broken-away in successive planes from right to left, corresponding to lines A A, B B, C C, and D D of Fig. 5. Fig. 5 is an enlarged crosssectional view of one of the valve chambers as shown in Fig. 1.

pedal mechanism, as in Fig. 2. Fig gis' a same on line 9--.9 and 10+10 of'Fig. Fig.

bperati'ng mechanism, similarto Figfi. Fig.

12 is a sectional elevation of the same taken on lme 1212 of Fig. 11. and. 16 show an alternative arrangement of Specification of Letters Patent. Application filed November 2, 1906. SeriaiNo. 341,755.

hinge the two parts together at r. rangement is clearly shown in F g. l. When the keys are played by hand the hinge r is Fig.6 is a partial plan View of some of the'valve rods. l 1g. 7 is an enlarged detail showing theloud Figs. 13, 14,15

Patented Aug. e, 1908.

the expression valves and four different positions thereof. I i

Referring to the drawings: he piano casing and frame consist of the usua back K,

top L, front-M, key-bed N, wires P, and contains the usual mechanism Q adapted to be operated by the various keys K in the ordinary manner. Within the casing I mount the necessary apparatus to manipulate said mechanism Q automatically by pneumatic One feature of the invention relates to the construction of the keys R, which I prefer to arrange so that they will not be depressed When the instrument is automatically operated. For this purpose I divide the rear portion of each key It as shown at 1', Fig. 1, and

The arinoperative, and'the rod' 14 which operates the piano action is raised in the ordinary manner by depressing a key R. \Vhen played automatically the action comes through hammer 43, as hereinafter described,. and lifts the hinged part of the key, thus operating the piano action through rod 14 without moving the forward part of thekeys B. By this means the felts which so port the keys remain with their initial so tness and are not hardened by any amount of mechanical operation of the piano.

The music roll 15 and take-up spool 16 are mounted in compartments 1? and 18 of box 19. They are adapted to convey the music sheet 20 transferably over a series of a ertures 21 in the abutment or tracker boarr 22 in a well known manner. The motor 23, of usual construction, is mounted opposite box 19 and serves to transfer the music sheet 20 through the agency of mechanism to be described. From apertures 21 flexible tubes 25, one for each key to be operated, furnish pneumatic connection with the interconnected chambers 26, 27, 28, arranged in super'posed position beneath key-bed N These are open to eachother at each end through channels 29,30, and'they connect through suitable valve-boxesBl, 32, 33 and 34 to air chamber 35, whence tubes 36 and 37 lead to exhausters 38 and 39,

located within the lower portion of the piano casing, and operated by foot levers 40, 41.

; ."ihe' general operation will .be briefly de-' scribed, after which the mechanism will be taken-up in detail.

When foot levers 40, 41 are operated, air is drawn from tubes 25 and valve chambers 26, 27 and 28, creating practically a vacuum therein. As music sheet 20 is slowly transferred from roll 15 to take-up spool 16, through the agency of motor 23, (which is pneumatically connected to the vacuum system by pi e 42) some of the apertures 21 are successively or simultaneously uncovered by the usual perforations in music sheet 20. This releases the vacuum in each correspond ing tube 25, operating corresponding puppet valves mounted in conjunction with valve chambers 26, 27 and 28, thereby causing the corresponding hammers 43 to-operate the mechanism Q, as though the corresponding key It had been depressed.

An important feature of the invention relates to the simplification and condensation of the key-operatirig mechanism.

Referring to Figs. 1, 2, 4 and 5,v.alve chambers 26, 27 and 28 are divided near the middle by walls 45, so that the right half exhausts through channel 29' and the left half through channel 30. Thus, a more even vacuum is maintained. and all the notes are struck with more nearly uniform forcel Describing one of the units, each tube 25 ends in a separate vestibule 50 (see Fig. 5) which is individual toeach tube but is (onnected to the common valve chamber 26' by a pin-hole 51. Pin-hole 51 serves to exhaust rapidly the slight amount of air which is within tube 25, but is not large enough to appreciably aiiect the vacuum in chamber 26 when aperture 21 is uncovered. A larger opening 52 between chambers 50 and 26 is covered by flexible covering 53, to which is fastened the lower end of valve stem. 54, carrying two puppet valves 55 and 56. Puppet valve 55 serves to close port 57 and puppet valve 56 controls port 58. A guide bar 59 holds stem 54 ineentral position. Between ports 57 and 58is a side outlet 60 connecting to a secondary individual diaphragm chamber 61, whose opening to valve chamber 26 is covered by the flexible diaphragm 62. Diaphragm 62 is reinforced by a stifl' plate 63- to compel uniform action and prevent buckling. Underneath each plate 63 and slidably journaled in the bottom wall of valve chamber 26 is a striking pin 64, positioned to engage the inner end of a pivoted lever 65, whose outer end carries a vertical rod 66 slidably journaled in key-bed N and provided at its upper end with the padded hammer 43.

Fig. 5 shows my preferred form of pivoting levers so that any one can be removed without disturbing the rest. Each lever has for a pivot a short pin 215, held in place by screws 216, 216. p

The individual tubes 25 lead to individual vestibules or pockets 50 in the valve champuppet valve 55 to close port 57 and puppet valve 56 to open port 58, thus cutting out the secondary diaphragm chamber 61 from thevacuum system and opening it to the atmosphere, whereby its vacuum is instantly released. This release distends downwardly diaphragm 62, causing striking pin 64 to descend and depress the inner end of lever 65,

thereby raising the outer end of same and causing hammer 43 to raise the hinged inner end of key It and operate the mechanism Q, as before mentioned. This arrangement of a common vacuum chamber with a series of adj accnt individual chambers, having a pneumatic connection directly to the vacuum chamber and a mechanical connection directly to the piano action, contributes greatly to the simplicity of construction and accuracy and delicacy of performance of the a paratus. l hen the perforation in music sl eet 20 has )assed the aperture 21, avacuum is quickly rei'ormed in vestibule 50 by means ofpin-hole 51., whereupon stem 54 falls, opening port 57 and closing )ort 53. The vacuum in chamber 61 is thus reformed, whereupon the weight of the various parts causes the outer end of lever 65 to descend again, raising the inner end and pin 64 and completing the restoration of positions illus trated in Fig. 5.

To equalizethe pulsating effect upon the main vacuum in air chamber 35.caused by the action of foot levers 40, 41, I provide storage reservoirs 70, 71, preferably mounted upon exhausters 38, 39' and controlled by valves 72, 73. Air is first drawn through tubes 36 and 37 to reservoirs 70, 71 and thence to exhausters 38 and 39.

The springs 212, 212, control exhausters 38 and39; and springs 213, 213 control reservoir bellows 70 and 71.

Attention is, however, called to the relatively small capacity of the valve chambers and connecting passages, as compared with those employed in previously-constructed instruments, especially valve chambers 26, 27 and All assages are large enough for easy flow of air, nit by the construction here shown it is possible by a single, forceful motion on the pedals to emphasize a particular note elimination of capacity from the vacuum system. The 0 eration of these parts is furtherimproved liy arranging the cxhausters to operate upon a vertical axis, which is set in the corner of the piano casing, while the This responsiveness is due to the means the two combine to utilize the avail- 40, 41 is illustrated in Figs. 1, 2 and 3, and

the

- inner end with a sprocket wheel 91 rigidly" rotatably mounted another sprocketwheel 96,

1 gaging sprocket wheel 99, ri idly mounted on yokes 105 and 106 respectively, which leave good contact .against apertures 21, and for efficiency or size of either.

rigidly mounted-*on a-sliding shaft 94, slidably' .Intermediate between these two sprocket .brace 24, and adapted at its lower end to 'be engagedby rod 115'to. cause winding or unof an arm 116 pivoted to brace 24 at ill7-and reservoirs 70,.71 operate upon vertical axes set nearer the center of the piano. By this able space completely Without sacrificing the The linkage eonnectin 'exhausters 38 and 39 to-foot levers consists of ball-end-links "7 5, 76, arranged at opposite ends of levers 77, 78 ivot'ally mounted in standards 7 9,7 9, 79. he lower ends of'foot levers 40, 41 are pivotally supported upon a floor rest 80, which is adapted to be raised from the floor when not in use. To accomplish this, I connect the fulcrum 81 by a'link 82 to 'a second fulcrum 83 within piano casing, and hang to fulcrum 81 a paw '84 which normally rests upon the floor of said casing. When foot rest is raised the notch 85 in pawl '84 en ages the front edge of the casing and locks t foot levers in raised position. I

Referring to Figs. '1, 2, 1'1 and 12, tl1emech hemotor 23 is. of ordinary construction, and its shaft'90 is provided at its secured thereto." Sprocket wheel 91 is conef nected by chain ..9.2 to a second wheel 93,

mounted in box '19and' bearing 95, Upon the oppositeend of shaft 94 is slidably and from which a chain 97-. runs to an adjustable idler sprocket wheel 98 mounted on box 19,- the outer side of said chain onitsreturn enthe shaftf100 which turns t e music roll 15.

chains 92 and 97 is a third chain 101 connect ing asprocket wheel 102, also slidably and rotatably mounted on shaft 1.04 which operates take-u spool 16. Sprockets 96 and 102 are each he (1 against sliding with shaft 94 by them free to rotate. 0n theiropposed faces are mounted pins 107, 108 posit1oned for engagement'respectively by pins 109, 110 on collar 111 rigidly secured to. shaft 94. Be tween-sprockets 102. and 93, is a shift collar 112 secured to shaft 94 and operated by shift lever 113 pivotal'ly' -mounted at 114 upo11,

winding of music-sheet 20, 'as desired.

It s necessary to keep a certam tension upon music-sheet 20 when playlng to insure securing this I provide a brake, in the. form normally held against the face of sprocket 96 sprocket 10.2.. The motor 23 being in opera I moves to the left and its pin109 eng'a es pin by spring 118-. When rod 115 operates to cause rewinding of music-sheet 20, a button 1 19, at itsend, releases saidbrake action by holding arm 116 away from said sprocket 96. I

The adjustability of sprocket 98 is shown 1 in Fig. 12 and consists of a plate 120 in which sprocket 98 is journaled, theouter-end of said plate-being secured to box 19 by screw 121.

and intermediate screw 122 inslot 123.

In addition to the ordinary spring sockets- 136, 137, at the left ends of music roll 15 and. take-up spool16, I provide adjusting means for regulating laterally 'the position 0 musicsheet 20. For this-purpose threaded socket ieces 138, 139 are screwed into the rightand side wall of box .19, and'haveche'ck nuts 140, 140 for locking the socket pieces in any desired position. These socket pieces 138, 139 carry their respective shafts 100 and 104, which are bored at their inner ends and perforated' to receive the spindles of music roll 15 and take up sp oolf16 and locking pins 141,141. I In Fig. 1 1 the parts are shown not in operation by .reason;.of'the factthat collar 1 11 is' g; midway between" sprockets 96 and 102. When rod 115 is moved to the right, shiftlever 113 'caufseslcollar 111 to move to the right .and'engageitspin 110 with pin 108 on 90 t1on,*takeu spool l6'is caused to revolve and wind on it t e musicesheet 20, causing the instrument-to play; When rod 115 is moved to its extreme left-hand .position,i.collar 111 95 107 on sprocket'96, causing music .rol to-re volve-in the opposite direction for rewinding music-sheet 20 at the conclusion of the playing operation. A a During the rewind it is desirable to accom- 19o plish two things: first, to cut out the valve chambers 26, 27 and 28 to preventiplaying; and second, to speed u the motor to accelerw. ate the operation. so, during the playing it is desirableto vary the tempo as well 5 .as to varythe vvolume'of sound. in ways different from What is accomplished by the or-' dinary soft and loud pedal mechanism. 1 provide-two series of valve boxes for controlling the vacuum in the various tubes, as follows: Referring to Figs. 2, .8, 9 and 10,

is a valve box containing two valves 146 and 14-7 separated blyi a semi-partition 148.

Valve 146 controls t tempo and is arranged to reciprocate over a narrowelon- 5 gated opening 149 in the-floor of box 145. Valve 147 controls therewind and is adapted to close or open the aperture 150. Beneath each opening. 149- and 150 are separate chambers 151 and 152 respectively, the 120 former communicating byme-ans of aperture 154 with a small controlling bellows 153, having a control spring 214 (Fig.9); and the lattercommun'icating with bellows 153 by means of opening 155, and also with main air 125 chamber 35 bymeans of tube 156. Pipe 42., before referred to, connects motor 23 with valvebox 145. During thep'laying opera-- tion. valve 147 covers aperture 1 50- and valve 146'is manipulate to uncover so mueh ($130 drawn toward each other one over 1 62 r m. K51) opening 149 as is necessary to give the do sired tempo, it beingsvell known that the faster air is Withdrawn from motor 23 the faster it willv operate, correspondingly increasii'ig the speed of music-sheet 20. r'iir is drawn from motor 23, through pipe alto valve box 1 15, thence by opemn 149 to chamber 151 and bellows 153, thence through aperture 155 to chamber 15?,tube 156 to main air chamber 35. Theto and fro action of the regulating bellows 153 is familiar to those skilled in the art, and needs no further explanation. During rewind valve 147 is open, allowing the air from motor 23 to by pass bellows 153, thus insuring quicker action. At each extremity of air chamber 35 is mounted a pair of valve boxes previously referred to as 31, 32, 33 and 34. Valve boxes 31 and 33 each contain a simple slide valve 160 for opening and closing apertures 161 to cut in and out valve chambers 26, 27, and 28 with the exhaust system during playing and rewind respectively. Valve boxes 32 and 34: communicate with air chamber 35 through openings 164, 16a and regulating bellows 165, 165 and also through ports 167, 168 controlled by expression valves 162, 163. These regulating l'iellovis 165 are used during ordinary playing. 1 have arranged the valves 162 and 163 so thatit is possible by a single control lever, as hereinafter described, to produce a loud treble with a softened bass, or the reverse, or to malrc both treble and loud or both soft. iii the position shown in Fig. 4 both treble and bass are loud, both bellows 1% beingbypassed. H valves .62 and 163 are tags both ports 167, 168, Will be closed, throwing the air through both bellows 165 and m. both treble and bass'soft. Drawn afoot stage closer together, port 16? opens I 168 remaining closed. his gives sort archie and loud bass. The next A 167 and opens 168, giving sr loud treble. in the above ar agernmt, valve 162 is in two arts, separated on the valve rod by the width of the port.

An alternative arrangement, in which eaeh valve is a single block, is shown in Figs. 13, 1 1, 15 and 16, Which represent successive positions. Each valve has sufficient lap to cover its port in two positions, and one a lead over the other. ports are open, the piano playing loud. the next stage, Fig. 141, the lead of valve 163 has closed its port168, port 167 remaining open. in the next stage, Fig. .15, the lap of valve 163 maintains port 168 closed, although 167 is the fourth stage, Fig. 18, the lead of 163 has opened port 168 While the lap oi. vaive162 maintains port 167 stili close...

Within the. easing is nenhan' the lone 31, 32, 33 and 3% I Thus, in 18, both rod 260 connected to valve 146. also closed; and 1n the feet. For this purpose I provide two levers 170 and 171 both pivoted loosely, at 172 on. a bracket 173 secured to the piano casing. See Figs. and 7. Lever 170 is positioned so that its free end extends beneath the paddle 174 of the bent rod 175. Its free end receives loosely the pm 176 fixed to the upper end of the ordinary loud pedal rod 177. Positioned on lever 170 and etween pivot 172 and paddle 1741 IS a threaded screw 178 adapted to receive ad justably the blow of a lug 179 on the side of lever 171. To the lower end of lever 171 is attached a cord or wire leading to a bent lever 180 pivoted in kcy-bed N and provided With a handle 181 in front of the keys R. Rocking lever 180 by means of handle 181 causes lug 179 to strike screw 178 and raise lever 170, and by this means rock bent rod 175 so that it shall simultaneously move all the mufflers 182 away from the strings. Rod 17 7 is meanwhile sta tionary, lever 170 merely sliding upon pin 176. When the pedal 87 is depressed, lever 170 is raised by rod 177 in the ordinary manner, in which case screw 178 merely moves away from lug 179.

To operate the various valves in boxes rovide a series of bent levers 183, .184, 185, ah pivotally mounted. in hey-bed N and provided with handles 186 187, 188 respectively.

1 mile 186 operates the gear shifter, the valve 1-17 and valves 160, 1o0 to change the direction of the rolling of i'nusic-sheet 20, to out in or out the valve chambers 26, 27 and and. to bypass bellows 153 for the Rod 115'is connected to the upper lever 190 pivoted at 191 to the casing (see 2) and having its lower end con nected to lever 183 by a rod 192. Valve stem 193 leads from valve 147 and is also connected to l ver 183. Valve stems 19 1, 19 1 lead from the valves 160, 160 to a crosspivoted at 196 to air box 35 (see and 6). The inner end of lever 195 acted by rod 19'? to a pivoted lever 198, .fhose upper end is connected to lever 183 by another link 199. Moving handle 186 to the left Will close valve 14-7, open valves 160, 160 and cause engagement of pins 108 and. 110 (Fig. 11) setting the playing mechanism in motion. lvloving handle 186 to the right Will reverse the motion of the musicsheet 20, open valve 1 17 to bypass bellows 1533;, thereby speeding up the motor, and close valves 166, 160 to cut out valve chambers see? 21111128.

Lever 188 controls the tempo by means of Linkage 20 attached to lever 188 moves an indicater 202 across a graduated scale 203 to note the desired change. Fig. 2.

The'expres ion lever 18 1 operates valve ()5,

to valves 162, 163 1 6O 1 66 shoulder 133 to engage a pin 134 in box 19 for temporarily removing these parts when ner ends to the piano frame and at their 25. This beinglocated close to the axis about I are operated. Cross-lever 206, pivoted at! 207 to air box 35 has its inner end engaged by the forked end of pivoted lever 208, which is connected to lever 184 by a link'209. See Figs. 2, 4 and 6.

The space here shown as occupied by the music roll, motor and related parts has not heretofore been considered convenient for that use, so far as I am aware, owing to the necessity of accessto the piano strings for tuning,.rendering it impracticable. Braces 24, 24 unite box 19 and motor 23 as a single unit, and ass st in providing a'simple means the instrument is to be tuned, thus e1iminat-- ing all the trouble ordinarily incidental to separating the connecting tubes and (pipes for that operation. Pivotally mounted u on box 19 and motor 23 near their upper e ges are two-hook-arms 125, 126 adapted to engage headed pins.127 onbrackets 128 secured'to the piano casing. Near the lower edges of box19 and motor 23 are two braces 129, 130, both rigidly secured at their inouter ends adapted to receive pivot pins 131, 132 mounted respectively in box 19 and motor 23.; Brace 129 has a projecting to limit the tilting movement when hooks 125, 126 are disengaged from pins 127. .Depending beneath box 19 is a U e shaped bracket 135 for supporting the various tubes which the box swings when turned outward, practicallyno displacement or withdrawal of the flexible tubes 25 is effectedby the outward movement of their upper ends.

While the invention has been here described as applied to apparatus working at subatinospheric pressure, such being considered preferable, it is obvious that the invention might be applied to apparatus working above atmospheric pressure, using compressed air instead of a vacuum; and in the claims the chambers, which have hereinbefore'been described as having the air exhausted from them, are referred to as power chambers, meaning by this term to cover either form of power. The specific method of applying the invention may be varied in other respects from that here shown, as will be readily understood by those skilled in the'art.

One advantage of using the exhaust system is seen in the very compact and simple arrangement of the valve or power chambers which this arrangement permits. Thus, the striking pin or rod 64 may pass loosely through its aperture, and under ordinary .conditions, when the same isinactive, said aperture is easily packed tight against air by an external pad 49, which is seated against the exterior of the power chamber, both by the weight of mechanism transmitted through the rod 66 and lever and by atdirection.

Y pneumatics mospheric pressure acting against the'vacu um within; while when said pin is depressed, the pneumatic being inaction, the amount of, air which leaksthrough. is readily cared for the main exhaust power. When not in action the exterior pad serves as a sto to limit the upward travel of pin 64, and t us hunt the stress on the diaphragms 62.

Allother feature of value in this construction is the economy of space itafi'ords by allowing the .diaphragms 62 to be retracted into their respective individual chambers while in action, thusaffording freer passage and reducing the requirements as to size of the valve or power chambers 26, 27 and 28. v

Attention is particularly called to the simple and inexpensive construction of the valve chambers 26 and'the adjacent power pneumatics, ports and valves. Thus, referring to Figs. 4 and 5,-it will-be seen that the top of each valve chamber 26, 27 and 28 may consist of a single board,'in which there are a series of recesses 61, the whole covered over with a single strip of leather 62, while the passage 60 and the ports 57, 58 are made simply by boring two holes in the same board..

As explained above, the exterior disk 49 constitutes a-pad to pack the aperture through which striking pin 64 passesfthus maintain ing the chamber tight at all pins which are in active. The chamber may be made equally tight when the pins are active by placing a pad 47 on the inner head 48 of rod 64 of suit able thickness to seat against the inside of the chamber when the pneumatic is expanded; and this constitutes a stop to limit the stress onthe diaphragm 62 in the downward Claims:

1. A pneumatic action, comprising a power chamber, in combination with a series of individual power pneumatics, each having a flexible actuating wall between it and the power chamber, and also having a ort to the power chamber and. a, port to t e atmoshere; a tracker board; ducts thence, each aving 'a flexible partition separating it from the power chamber and a pin-hole connection thereto and valves for said ports, actu- Y ated by fluctuation of said partitions.

2. A pneumatic action, power chamber; a series of individual power arranged on one wall thereof and expansible into the chamber; and rods piercing a closed portion of the opposite wall of the chamber, movable endwise therethroug'hin the line of action --of said'pneumatics, and exterior mechanism engaging said rods. r

v 3. A pneumatic action, coin rising a power chamber having individua recesses interiorly in one wall thereof, and a flexible diaphragm partition for each, forming power pneumatics; there being an extension of each recess within the wall, and passages comprising a -t the chamber and through the wall transversely intersecting extension and forming ports therefrom l to the atmosphere; and means to operate each valves for said ports, the same.-

4. A neumatic 7 action, comprising, a power c amber; atracker boardpducts therefrom, each communicating with the power chamber by a in-hole and separated therefrom by a flexib e diaphragm; a power pneumatic, separated from the power chamer by a flexible partition and connected .by a port, and also having phere; said ports being controlled by means movable by the flexible diaphragm; and a connection from said flexible partition to th mechanism that is to be operated.

5. A pneumatic action, comprising a power chamber having a wall containing within itself power pneumatics and ports therefrom to the chamber and to the atmosphere; exterior mechanism; and power transmission ro'ds engaging the power pneua port to the atmosi Witnesses:

matics within thechamber, having bearings in a wall of the chamber, and engaging sald mechanism outside the chamber; with valves 1 for said ports and operating means therefor.

6. A pneumatic action comprising a power chamber having a Wall containin a series of recesses, diaphragms separating them from the chamber and ports connecting them individually to the chamber and to the atmosphere; valves therefor; exterior mechanism; and power transmission rods engaging the diaphragms within the chamber, having slide bearings in the opposite wall, and engaging said mechanism outside the chamber.

In testimony whereof I have affixed my signature in presence of two witnesses, at Boston October 27th 1906.

GUSTAF WM. PAULSON.

JEROME 0. SMITH, EVERETT E. KENT. 

